| In recent years,oil spills occur frequently,which not only causes serious energy waste,but also causes serious environmental pollution.The oil spill can spread rapidly on the water surface and form a large area of oil film,which has a sustained impact on the nearby marine ecosystem.It is a common method to clean up oil spills by using adsorption materials.Organic adsorption materials,especially fiber materials,have attracted much attention because of their low price,strong adsorption capacity,rich resources,stable chemical properties,and easy large-scale production.Cruciate polyester fiber is one of the important varieties of differential fiber.It mainly uses physical methods to change the morphology and structure of the polymer to change the fiber properties.The typical application is Coolmax moisture adsorption and quick drying fabric.The cruciate polyester fiber has certain hydrophobicity,but its hydrophobicity is not enough to achieve oil-water separation.To realize the application of cruciate polyester fiber in the field of oil-water separation,this paper focuses on the hydrophobic modification of cruciate polyester fiber,the rapid oil adsorption,and oil-water separation of cruciate polyester fiber flocs and super hydrophobic directional fiber assembly were studied.The main research contents are as follows:The cruciate polyester fiber was modified with methyltrichlorosilane by vapor deposition.The water contact angle was 152.67°,the water shedding angle is 9.5°,the water droplets can move freely on the surface of the fiber,which can realize the self-cleaning of the fiber surface,and the water adsorption capacity is 1.74 g/g.The prepared superhydrophobic cruciate polyester fiber has strong superhydrophobic stability,can resist high temperature,ultraviolet radiation,and solvent immersion for 360 h,and its water contact angle remains at 150°above.Superhydrophobic cruciate polyester/low melting point fiber(SCPET/ES)flocs have excellent oil adsorption capacity.The oil adsorption capacity of SCPET/ES flocs to diesel oil,soybean oil,engine oil 0w-20,engine oil 5W-40,and engine oil 20W-50 was 41.64 g/g,53.95 g/g,57.64 g/g,61.00 g/g,and 71.49 g/g respectively.The oil retention capacity of the five kinds of oil reached 90%,and 89.15-94.67%of the oil can be recovered.After 10adsorption-desorption cycles,the adsorption capacity with different viscosity oil can still be maintained at least 70%.The oil adsorption capacity of SCPET/ES oriented fiber assembly for diesel oil,soybean oil,engine oil 0w-20,engine oil 5W-40,and engine oil 20W-50 was 33.50 g/g,54.36 g/g,56.15 g/g,63.76 g/g,and 91.67 g/g,respectively.For five kinds of oil,the oil retention capacity is more than 90%,and the recovery capacity is 90.34-94.53%.After 10adsorption-desorption cycles,it can maintain more than 80%oil adsorption capacity.The permeation time of oils with different viscosities in the orientation direction of SCPET/ES assembly is 1.0-4.0 s.The penetration time in SCPET/ES flocs is 2.0-5.0 s,and the diffusion time in superhydrophobic polyester/low melting point fiber(SPET/ES)flocs is extended to2.2-7.0 s.SCPET/ES fiber flocs have excellent oil-water selectivity,which can realize the cleaning and recovery of floating oil and underwater oil.SCPET/ES fiber flocs were used as the filter element of gravity-driven oil-water filtration device for oil-water separation.The separation flux of SCPET/ES fiber flocs for high-density heavy oil was 45294 L·m-2·h-1,and for low-density,light oil was 21176-23026 L·m-2·h-1.The oil-water separation efficiency was above 99%,and the separation efficiency for high concentration brine-oil mixture was above99%.By connecting SCPET/ES directional fiber assembly with an oil suction pump,the oil spill can be continuously collected on the water surface.The separation flux can reach 53079L·m-2·h-1 for low viscosity diesel oil and 11795 L·m-2·h-1 for high viscosity oil 20W-50.The separation of emulsion can be achieved by oscillating method.The separation efficiencies of SCPET/ES fiber floc for water-in-n-hexane,water-in-toluene,water-in-diesel oil and water-in-soybean oil emulsion are 99.76%,99.41%,99.63%and 99.70%respectively.For fiber assembly with different densities,with the increase of density,the oil adsorption capacity decreases,the oil retention capacity remains unchanged,and the oil recovery capacity decreases.When the same density of fiber assembly adsorbed different properties of the oil,the fastest adsorption was methanol,then diesel,and the slowest was soybean oil.The liquid adsorption coefficient decreased with the increase of liquid viscosity.In the same oil and different filling density fiber assembly,the liquid adsorption coefficient increases with the increase of assembly density.The results show that the liquid adsorption rate of fiber oriented assembly is better than that of disordered fibers,and the liquid adsorption coefficient of cross fiber assembly is higher than that of round fiber assembly.Therefore,fiber flocs are suitable for emergency oil recovery,and 3D oriented fiber assembly is more suitable for recovering large amount of leaked oil. |
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